In order to obtain high sensitivity and reduce residual coloration after the processing (residual color) of a silver halide photographic light-sensitive material, a great deal of efforts have heretofore been made. Sensitizing dyes used for spectral sensitization are known to have great effect on the capabilities of a silver halide photographic light-sensitive material. Even a very small difference in the structure of sensitizing dyes greatly affects the photographic capabilities such as sensitivity, fog and storage storability and it is difficult to anticipate the effect beforehand. Many researchers have conventionally synthesized a large number of sensitizing dyes and examined photographic capabilities thereof. As the sensitizing dye, those having a partial structure of a nitrogen-containing heterocyclic ring having a carboxyalkyl group are commonly used. Well known examples of the carboxyalkyl group include a carboxymethyl group, a 2-carboxyethyl group and a 3-carboxypropyl group. Carboxyalkyl groups other than these are, however, little studied and their effect on the photographic capabilities cannot be actually estimated at all at present.
Under these circumstances, sensitizing dyes capable of spectral sensitization while attaining high sensitivity without causing any adverse effect such as fog and reducing the residual color have heretofore been demanded.